New Jersey fund manager and "merger arbitrage" specialist Alpine Associates has acquired a 5.3 per cent stake in ASX-listed hotel and resort operator Mantra Group ahead of its $1.2 billion merger with French giant Accor.

Alpine, which was founded in 1976 and has $US1.8 billion of assets under management spent around $60 million acquiring Mantra shares at prices ranging from $3.84 and $3.91 with its first purchases made in October last year.